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Old 11-13-2008
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Stern designs and trade offs

THis is a carry over from another thread so as not to take over another thread.

The question was raised as to whether (and why) some boats have more of an issue in a following sea than others. I tern this, "The tail wagging the dog". In effect, it is when you are running with a following sea either at the quarter or directly astern and the stern is seriously "pushed" with the seas. THis is more prominent with the steeper seas than flat seas, but I imagine many people have been exposed to some aspect of it.

I am comparing two boats. One boat is the traditional, offshore type of boat like a Tayana 42. The other is the more modern type of boat like a Catalina 400. The Tayana, when viewed from the bottom and stern (ignoring the canoe stern for a moment) has a soft chime and is fairly rounded on the bottom. It is very narrow at the stern and has very little wetted area exposed to the following sea. THe other boat is the Catalina 400. Its bottom is fairly flat and has a very wide stern.

I can attest, personally, that the Tayana handles better in a following sea than the wider, flatter boat. Why? It is my position that the stern of the Catalina exposes more wetted/hull area than the stern of the Tayana. Being that it is also flatter, it is harder to displace the force of the water. THis is especially apparent when you consider any pitching.

I have tried to illustrate it here. It is a bad illustration. I would apprecaite others comments as design is not my strength - at all. I am viewing this from first hand knowledge of time aboard the two boat types and a basic common sense approach.

- CD



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